Metabolic control in a state of decreased activation: modulation of red cell metabolism

Transcriptomics of Long-Term Meditation Practice: Evidence for Prevention or Reversal of Stress Effects Harmful to Health

Background and Objectives: Stress can overload adaptive mechanisms, leading to epigenetic effects harmful to health. Research on the reversal of these effects is in its infancy. Early results suggest some meditation techniques have health benefits that grow with repeated practice. This study focused on possible transcriptomic effects of 38 years of twice-daily Transcendental Meditation^® (TM^®) practice. Materials and Methods: First, using Illumina^® BeadChip microarray technology, differences in global gene expression in peripheral blood mononuclear cells (PBMCs) were sought between healthy practitioners and tightly matched controls (n = 12, age 65). Second, these microarray results were verified on a subset of genes using quantitative polymerase chain reaction (qPCR) and were validated using qPCR in larger TM and control groups (n = 45, age 63). Bioinformatics investigation employed Ingenuity^® Pathway Analysis (IPA^®), DAVID, Genomatix, and R packages. Results: The 200 genes and loci found to meet strict criteria for differential expression in the microarray experiment showed contrasting patterns of expression that distinguished the two groups. Differential expression relating to immune function and energy efficiency were most apparent. In the TM group, relative to the control, all 49 genes associated with inflammation were downregulated, while genes associated with antiviral and antibody components of the defense response were upregulated. The largest expression differences were shown by six genes related to erythrocyte function that appeared to reflect a condition of lower energy efficiency in the control group. Results supporting these gene expression differences were obtained with qPCR-measured expression both in the well-matched microarray groups and in the larger, less well-matched groups. Conclusions: These findings are consistent with predictions based on results from earlier randomized trials of meditation and may provide evidence for stress-related molecular mechanisms underlying reductions in anxiety, post-traumatic stress disorder (PTSD), cardiovascular disease (CVD), and other chronic disorders and diseases.

The Effects of Mindfulness-Based Stress Reduction for Family Caregivers: Systematic Review

Caring for patients with various conditions is demanding and stressful and can have a negative impact on both physical and psychological health. This paper reports a systematic review and critical appraisal of the evidence on the effectiveness of mindfulness-based stress reduction for the family caregivers of patients with various conditions. There were improvements in the self-rated psychological symptoms, such as stress, depression, anxiety and mindfulness. To conclude, mindfulness-based stress reduction, as a safe and transportable approach, has potential to improve the psychological symptoms in the caregivers of patients with various conditions.

Live cell imaging of the intracellular compartmentalization of the contaminate benzo[a]pyrene

This study investigates the cellular response of murine hepatoma cells to the polycyclic aromatic hydrocarbon benzo[a]pyrene (B[a]P) using two-photon and confocal laser scanning microscopy. The intracellular distribution of B[a]P and the B[a]P/AhR complex was visualized time- and concentration-dependent for up to 48 h of exposure. B[a]P was predominantly found in lipid droplets, endoplasmic reticulum and lysosomes, where B[a]P is collected and forms large aggregates. Changes in mitochondrial membrane potential and bleb formation due to high B[a]P concentrations were observed. The imaging data presented in this study provide new insights into the systemic cellular regulation following B[a]P exposure.

Sudarshan Kriya practitioners exhibit better antioxidant status and lower blood lactate levels

Oxidative stress may contribute to the pathophysiology of many chronic diseases. Since psychosocial stress increases oxidative stress, we conducted an exploratory study to investigate the effects of stress reduction with the Sudarshan Kriya (SK) program, on superoxide dismutase (SOD), catalase, glutathione and blood lactate levels in practitioners and non-practitioners of SK. Blood samples of ten practitioners of SK and 14 non-practitioners of any formal stress management technique were analyzed for SOD, catalase, glutathione and lactate levels. Differences between groups and subgroups were analyzed by t-test and correlations between variables compared using Pearson's correlation coefficient. Significantly lower levels of blood lactate (P=3.118e-10) and higher levels of SOD (P=0.0001415), glutathione (P=2.038e-06) and catalase (P=0.001565) were found in practitioners as compared to non-practitioners of SK, thereby suggesting that lower levels of blood lactate and better antioxidant status in practitioners are associated with regular practice of SK technique. However, this study needs to be conducted on a larger sample size to confirm this effect.

Ketosis with enhanced GABAergic tone promotes physiological changes in transcendental meditation

Transcendental meditation (TM) is a stylized form of physical and mental relaxation which is associated with changes in the secretion and release of several pituitary hormones. The hormonal changes induced by TM mimic the effects of the inhibitory neurotransmitter gamma aminobutyric acid (GABA). It is hypothesized that TM produces changes in pituitary hormone secretion by enhancing hypothalamic GABAergic tone as a result of TM associated ketosis. Ketosis enhances the entry of glutamate, the amino acid substrate of GABA into synaptosomes, making more glutamate available for conversion to GABA through the glutamate decarboxylase pathway.

Serum hormonal concentrations following transcendental meditation--potential role of gamma aminobutyric acid

Transcendental mediation (TM) is a stylized form of physical and mental relaxation which is associated with changes in the secretion and release of several pituitary hormones. The hormonal changes induced by TM mimic the effects of the inhibitory neurotransmitter gamma aminobutyric acid (GABA). It is hypothesized that TM produces changes in pituitary hormone secretion by enhancing hypothalamic GABAergic tone, and its anxiolytic effects by promoting GABAergic tone in specific areas of the brain. This mechanism is similar to the effects of synthetic anxiolytic and tranquilizing agents such as benzodiazepines that bind to components of the GABA-A (GABAA) receptor. TM, therefore, may produce relaxation by enhancing the effects of an endogenous neurotransmitter analogous to the effects of endorphins in runners who reportedly experience a 'runner's high'.

Use of transcendental meditation to relieve stress and promote health

The relief of stress is an important part of health promotion. This article examines the effects of transcendental meditation on stress and discusses how it can improve health.

Pharmacokinetics and biological activity of kinetensin in conscious sheep

Kinetensin is a nonapeptide, originally isolated from pepsin-treated plasma, that shares some sequence homology with the C-terminal end of neurotensin. The present study was designed to determine, by infusing kinetensin to conscious sheep, the pharmacokinetics and a neurotensin-like biological activity (pancreatic polypeptide response) of kinetensin. Kinetensin was rapidly metabolized, approximately 200-fold more rapidly than neurotensin. The majority of the metabolism occurred in the circulation as demonstrated both in vivo and in vitro. The lung and gut cleared kinetensin also. Inhibition of converting enzyme, present in highest concentration in the lung, abolished lung clearance but was without effect on kinetensin metabolism by the gut or in the general circulation. Arterial infusion of kinetensin which achieved high blood kinetensin levels at the pancreas did not increase plasma pancreatic polypeptide. We conclude that the extremely rapid degradation of exogenous kinetensin, together with the lack of biological activity, makes it unlikely that kinetensin plays a role as a circulating regulatory peptide. Nevertheless, since the putative kinetensin substrate circulates at microM concentrations, it is feasible that kinetensin is generated and metabolized at the target organ.

The physiology of meditation: a review. A wakeful hypometabolic integrated response

While for centuries a wakeful and tranquil state or experience variously called "samadhi," "pure awareness," or "enlightenment" had been said to be a normal experience and the goal of meditation in Vedic, Buddhist, and Taoist traditions, there was little known about this behavior until recently, when the practice of "transcendental meditation" (TM) became available for study in Western scientific laboratories. Derived from the Vedic tradition, TM is unique because it requires no special circumstances or effort for practice. Based upon a wide spectrum of physiological data on TM, we hypothesize that meditation is an integrated response with peripheral circulatory and metabolic changes subserving increased central nervous activity. Consistent with the subjective description of meditation as a very relaxed but, at the same time, a very alert state, it is likely that such findings during meditation as increased cardiac output, probable increased cerebral blood flow, and findings reminiscent of the "extraordinary" character of classical reports: apparent cessation of CO2 generation by muscle, fivefold plasma AVP elevation, and EEG synchrony play critical roles in this putative response.

Elevated serum dehydroepiandrosterone sulfate levels in practitioners of the Transcendental Meditation (TM) and TM-Sidhi programs

Serum dehydroepiandrosterone sulfate (DHEA-S) levels were measured in 270 men and 153 women who were experienced practitioners of the Transcendental Meditation (TM) and TM-Sidhi programs, mental techniques practiced twice daily, sitting quietly with the eyes closed. These were compared according to sex and 5-year age grouping to 799 male and 453 female nonmeditators. The mean DHEA-S levels in the TM group were higher in all 11 of the age groups measured in women and in 6 of 7 5-year age groups over 40 in men. There were no systematic differences in younger men. Simple regression using TM-group data revealed that this effect was independent of diet, body mass index, and exercise. The mean TM-group levels measured in all women and in the older men were generally comparable to those of nonmeditator groups 5 to 10 years younger. These findings suggest that some characteristics of TM practitioners are modifying the age-related deterioration in DHEA-S secretion by the adrenal cortex.

Biological potency of neurotensin metabolites in vivo: importance of alcohol 'fixation' of blood

Neurotensin (NT), a 13-amino acid peptide, is released from the ileum following a meal. It is metabolized principally by the kidney and in the circulation to N-terminal fragments and apparently rapidly degraded C-terminal fragments. The present study was designed to compare the biological activity (plasma pancreatic polypeptide response) and the clearance kinetics of NT(1-13), the N-terminal fragment NT(1-11) and the C-terminal fragment NT(8-13). To measure accurately the circulating concentrations of short-lived NT fragments in the circulation, a method was devised of collecting blood directly into alcohol ('alcohol fixation'). The alcohol fixation procedure prevented the post-collection losses of the C-terminal fragment NT(8-13) and established that, based on blood levels achieved, NT(8-13) had 70% of the pancreatic polypeptide stimulating potency of NT(1-13). Nevertheless, the metabolic clearance rate of NT(8-13) was about sevenfold higher than the intact molecule, NT(1-13), suggesting that circulating C-terminal fragments have a minor physiological role. When the N-terminal fragment NT(1-11) was infused, there was no sustained effect on pancreatic polypeptide secretion although it was cleared at a rate similar to that of NT(1-13). It is concluded that the use of alcohol fixation prevents post-collection losses of NT fragments and enables true biological potencies of short-lived fragments to be assessed. The biological activity of NT resides in the C-terminus which, once split from the protective N-terminus, is rapidly degraded in the circulation. The remaining intact but inactive N-terminus is relatively stable.

Extraction of neurotensin by the liver

1. Neurotensin is released from the intestine into the portal circulation and to exert a systemic effect it must traverse the liver intact. 2. The role of the liver in neurotensin clearance was examined using the isolated perfused rat liver preparation. Two concentrations of neurotensin were used to determine the extraction capacity of the liver. 3. Approximately 10% of the added neurotensin (with either dose) was extracted in a single pass through the liver. This extraction rate was low when compared to previous studies with cholecystokinin (60% extraction in a single pass) and vasoactive intestinal peptide (100%). 4. It is concluded that there is a small but high capacity for direct extraction of neurotensin. This low direct extraction percentage supports our previous contention that the major influence of the liver on the metabolism of neurotensin is by the release of neurotensin degrading peptidases into the circulation.

The vagus and neurotensin release in duodenal ulcer--clinical and experimental studies

Although meal-stimulated neurotensin release from the small intestine is inhibited by cholinergic blockade, it is uncertain whether this cholinergic mechanism involves the vagus. This study examines the role of the vagus in neurotensin release by first determining the effect of vagotomy on meal-stimulated plasma neurotensin in man and second, the effect on plasma neurotensin of electrical stimulation of the vagus in sheep. Six volunteers were studied 6-8 weeks after truncal vagotomy and pyloroplasty. Basal plasma neurotensin at 32(15-67) pmol/l (median, range) was greater than in normal controls at 17 (9-52) pmol/l (P less than 0.05). Following a standard meal, plasma neurotensin rose significantly (P less than 0.05), but similarly in both post-vagotomy and control groups to maxima of 74 (43-76) pmol/l and 52 (35-65) pmol/l, respectively. Basal plasma neurotensin in the six sheep was below the detection limit of the assay and remained undetectable during electrical stimulation of the vagus. Significant rises in plasma pancreatic polypeptide and gastrin confirmed the efficacy of the electrical stimulation. It is concluded that although the vagus might have a tonic inhibitory effect on basal plasma neurotensin, meal-stimulated neurotensin release is vagally independent. The inhibitory cholinergic influence on meal-stimulated release is most likely therefore to be mediated by cholinergic nerves of the enteric nervous system.

Effect of renal failure or portacaval shunt on release of neurotensin in man

Neurotensin-like immunoreactivity (NTLI) is released into the circulation following a meal. However, the factors influencing its degradation and metabolism are uncertain, but it is presumed that the kidneys and liver are involved. This study has determined the release of NTLI after a liquid fat meal (200 ml 20% Intralipid) in 10 healthy control subjects, five patients with stable chronic renal failure (CRF), and five patients after a portacaval shunt (PCS), to assess the possible role of the liver and kidney in NTLI metabolism. NTLI was measured by radioimmunoassay using both specific C and N terminally directed antisera. The results showed: Basal NTLI levels are similar in controls, after PCS, and in CRF. A liquid fat meal produces a single early peak of NTLI and levels are greater after PCS than in controls or CRF. Levels return much more slowly to basal in CRF and after PCS. Thus it is likely that both the liver and kidney are involved in the metabolism and clearance of NTLI.

Marked reduction of forearm carbon dioxide production during states of decreased metabolism

We studied oxygen consumption, carbon dioxide production and acid/base changes in 62 subjects during two hypometabolic states (35 during transcendental mediation and 27 during unstylized rest). The results indicate that, during these hypometabolic states, arterial-venous CO2 content difference declines, and that during transcendental meditation, arterial-venous CO2 content difference briefly disappears. This change is due to both an increase of arterial CO2 content and a decrease of venous CO2 content. Similar, but opposite and smaller, changes occurred in arterial and venous O2 content. Respiratory quotient was low at all times and decreased during the hypometabolic states. These results are consistent with the hypothesis that, during hypometabolic states significant ketogenesis is induced, and provision of energy from the normally predominant process of beta-oxidation of fat becomes sufficient to provide energy for greatly reduced activity without entry of two carbon fragments into the tricarboxylic acid cycle; under these conditions, biochemical feedback mechanisms inhibit the tricarboxylic acid cycle. The net result of these metabolic changes could explain the major observations: absent carbon dioxide production while oxygen consumption declines but continues and the venous effluent contains more acid.

Plasma thyroid hormones, thyroid stimulating hormone, and insulin during acute hypometabolic states in man

Acute behavioral rest states in man are associated with marked hormonal and metabolic changes. In order to complete a hormonal profile of these states and to identify possible metabolic regulators, we measured thyroid hormones (T3 and T4), thyroid stimulating hormone (TSH), and insulin during the stylized mental practice of "transcendental mediation" (TM) and during ordinary unstylized eyes closed rest. Except for TSH, which declined acutely, hormone levels were normal and stable throughout the experiment. The stability of T3 and T4, and insulin make it unlikely that these hormones regulate the acute metabolic changes associated with these behavioral states. Decreased TSH, along with stable thyroid hormone levels, may suggest change of the set point for feedback control of TSH secretion during TM and is consistent with primarily neural modulation of TSH secretion by this behavior.

The TM-Sidhi programme, age, and brief tests of perceptual-motor speed and nonverbal intelligence

Three brief tests that assess perceptual-motor speed and two that assess nonverbal intelligence were administered to individuals who were practicing the Transcendental Meditation and TM-Sidhi programme. Multiple regression analyses showed that when motivation (measured on a 5-point self-rating scale), age, sex, education, and duration of practice of the Transcendental Meditation technique were held constant, number of months of practice of the TM-Sidhi programme significantly predicted higher performance on two of the perceptual-motor speed tests and both tests of intelligence. Age predicted lower scores on the same tests.

Biochemical indices associated with meditation practice: a literature review

Research findings on biochemical responsivity to meditation are reviewed. Although there are some contradictory and inconclusive outcomes, there is nevertheless sufficient evidence of interest to warrant further investigation of this area. However, in the meantime, there is no compelling basis to conclude that meditation practice is associated with special state or trait effects at the biochemical level.

Modulation of red cell metabolism by states of decreased activation: comparison between states

Marked decline of red cell metabolism has been described during the acute state of decreased activation associated with the stylized mental technique of transcendental meditation (TM) in long-term meditators (5-10 years regular elicitation, TM instructors). It is not known whether unstylized rest is accompanied by a similar effect and it is not known what effector(s) may contribute to red cell metabolic changes in these states. In the present study ordinary, unstylized rest was found to be accompanied by small increase of red cell glycolytic rate. Apparently, either repeated elicitation of TM behavior or some special feature of this practice become associated with new mechanisms of metabolic control than those previously in operation. Although the data of this study do not permit isolation of the precise psychological determinants of this effect, the range of possible physiological effectors can be delimited. Blood pH, PCO2, PO2, and phosphate can be eliminated as significant for red cell metabolic control during both TM and rest, and based upon related studies, several known hormones such as insulin, T3, T4, arginine vasopressin, oxytocin, prolactin and growth hormone can also be eliminated as responsible effector(s).

Quantitation and characterization of human plasma neurotensin-like immunoreactivity in response to a meal

The secretion and metabolism of endogeneous neurotensin-like immunoreactivities after a test meal were studied in five healthy human subjects. Intact neurotensin and the N-terminal metabolic fragment, neurotensin 1-8, were quantified by radioimmunoassay with C- and N-terminally directed antisera in conjunction with gel filtration of plasma samples obtained at timed intervals. Both C- and N-terminal neurotensin-like immunoreactivities rose after the meal, reaching a plateau level after 20 and 30 min, respectively. During the plateau phase, which lasted for the rest of the experimental period of 180 min, the molar ratio of intact neurotensin to neurotensin 1-8 remained approximately constant at 1:4.6. Meal-stimulated immunoreactive neurotensin appeared to be metabolized in a manner comparable to that of exogenously infused neurotensin in man. The results suggest that intact neurotensin is secreted at an approximately constant rate during the plateau phase. The relatively low plateau level of neurotensin 1-8, which has a much longer half-life than intact neurotensin in the circulation, implies that only a fraction of the secreted intact neurotensin is metabolized to neurotensin 1-8, indicating the existence of alternative pathways of neurotensin metabolism.